1. Field of the Invention
The present invention relates to a photosensitive material developing apparatus for developing an imagewise exposed photosensitive material by means of a developer. More particularly, the present invention pertains to a photosensitive material developing apparatus which is most suitable for producing lithographic printing plates.
2. Description of the Related Art
A typical conventional automatic developing machine for processing a multiplicity of lithographic printing plates has heretofore been arranged such that a photosensitive material is transported through a plurality of pairs of rollers while being clamped thereby, and in the course of the transportation, a developer is applied to the surface of the imagewise exposed light-sensitive layer of the photosensitive material (herein after refers to as "the exposed surface of the photosensitive material") to conduct a developing operation. This developer is applied to the exposed surface by a spray or other similar means so as to dissolve or swell either the exposed area or the non-exposed area, and then brushed off.
The developer which has already been used for the developing operation is generally recirculated for reuse. During such repetitive use of the developer, however, a component in the photosensitive layer of the photosensitive material dissolves out and consumes an effective component in the developer, thus causing the developer to be fatigued and thereby deteriorated. In addition, when the developer is alkaline, it gradually absorbs carbon dioxide gas in the air as time goes by, so that the developer is neutralized little by little to lower the alkaline strength, resulting in fatigue with age, and thus causing the developer to be deteriorated.
To relieve a developer of such fatigue, means have already been proposed wherein the fatigue is relieved by supplying a developing replenisher either continuously or intermittently in accordance with the amount by which the developer is used up for development, such as those disclosed in the specifications of Japanese Patent Laid-Open No. 144,502/1975, U.S. Pat. No. 4,259,434 and British Pat. No. 2,046,931. These prior arts suffer, however, from the problem that the composition of the developer becomes slightly different from that in a previous developing operation, which means that photosensitive materials which are, strictly speaking, different from each other in terms of performance are produced for each time.
For this reason, a means wherein a developer which has already been used for development is not reused but disposed has been contrived. This prior art, however, needs a relatively large amount of developer and is therefore uneconomical. Further, there has been still another known means wherein the amount of developer used is reduced, and the developer remaining on the exposed area is removed by rubbing the photosensitive material with a brush or a sponge. However, this prior art also suffers from the problems that development cannot satisfactorily be effected, and the matter to be printed is liable to be stained during printing.